[FFmpeg-devel] [PATCH] avfilter: add compensationdelay filter

[Moritz Barsnick]

On Wed, Nov 25, 2015 at 09:48:36 +0100, Paul B Mahol wrote:
> Patch attached.

> +For example, you have recorded guitar with two microphones placed in
> +different location. Because the front of sound wave has fixed speed in
> +normal conditions, the phasing of microphones can vary and depends on
> +their location and interposition. The best sound mix you will get when
> +these microphones are in phase (synchronized). Note that distance of
> +~30 cm between microphones makes one microphone to capture signal in
> +antiphase to another microphone. That makes the final mix sounding moody.
> +This filter helps to solve phasing problems by adding different delays
> +to each microphone track and make them synchronized.

  For example, you have recorded a guitar with two microphones placed
  in different locations.

This part I don't actually understand (is the fixed speed really the
reason?), but I fixed the grammar anyway:

  Because the front of sound wave travels at fixed speed in normal
  conditions, the phasing of microphones can vary and depends on their
  location and interposition.

  The best sound mix can be achieved when these microphones are in
  phase (synchronized). Note that a difference of ~30 cm in the
  distances between source and microphones leads to one microphone
  capturing its signal in antiphase to the other.

  That makes the final mix sound moody. This filter helps to solve
  phasing problems by adding different delays to each microphone track
  and make them synchronized.

I'm not sure "synchronized" is the correct term though, but I'm no
expert.

Here, I might avoid the "you" form in favor of passive, but I guess
it's okay as it is:

  The best results can be achieved when you take one track as base and
  synchronize other tracks one by one with it.


> + at item mm
> +Set millimeters distance. This is compensation distance for fine tuning.
> +
> + at item cm
> +Set cm distance. This is compensation distance for tighten distance setup.

for tightening

> + at item m
> +Set meters distance. This is compensation distance for hard distance setup.
> +
> + at item dry
> +Set dry amount. Amount of unprocessed (dry) signal.
> +
> + at item wet
> +Set wet amount. Amount of processed (wet) signal.
> +
> + at item temp
> +Set temperature degree in Celzius. This is the temperature of the environment.

Celsius

> + at end table

Would you like to document the defaults?

Moritz